Category: Mechanical Engineering

Latest multiple choice questions with answers for mechanical engineering students.

Mechanical Engineering MCQs [Quiz 29]

Q1. Ultimate analysis of fuel is determination of percentage of
(a) carbon, hydrogen, nitrogen, sulphur, moisture
(b) fixed carbon, ash, volatile matter, moisture
(c) higher calorific value
(b) lower calorific value
(e) best analysis.

Q2. For combutsion of a fuel, following is essential
(a) correct fuel air ratio
(b) proper ignition temperature
(c) 02 to support combustion
(d) all the three above
(e) none of the above.

Q3. Spontaneous combustion is a phenomenon in which
(a) all the fuel burns instantaneously producing high energy release
(b) fuel burns with less air
(c) coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal
(d) explosion in furnace
(e) none of the above.

Q4. The economiser is used in boilers to
(a) increase thermal efficiency of boiler
(b) economise on fuel
(c) extract heat from the exhaust flue gases
(d) increase flue gas temperature
(e) to heat feed water by bled steam.

Q5. An economiser in a boiler
(a) increases steam pressure
(b) increases steam flow
(c) decreases fuel consumption
(d) decreases steam pressure
(e) increases life of boiler.

Q6. 02 content in atmospheric air on volume basis is
(a) 21%
(b) 23%
(d) 30%
(d) 40%
(e) 70%.

Q7. 02 content in atmospheric air on weight basis is
(a) 21%
(b) 23%
(c) 30%
(d) 40%
(e ) 70%.

Q8. Primary air is the air used to
(a) provide air around burners for obtaining optimum combustion
(b) transport and dry the coal
(c) convert CO (formed in lower zone of furnace) into C02 at higher zone
(d) air-delivered by forced draft fan
(e) none ot the above.

Q9. Sulphur content of fuels is very important to the plant operators because it
(a) has high heating value
(b) retards electric precipitation
(c) promotes complete combustion
(d) has highly corrosive effect
(e) facilitates ash removal.

Q10. Presence of moisture in fuel oil would
(a) keep the burner tips cool
(b) aid in proper combustion
(c) cause sputtering, possibly extinguish¬ing flame
(d) clean the nozzles
(e) reduce flame length

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